The treatment for alcohol and other drug disorders has been shown to be effective, yet previous research suggests that the quality of treatment received may differ based on client's race/ethnicity. The goal of this study is to increase our understanding of racial/ethnic differences in the quality of treatment for substance use disorders. Specifically, this study aims to: 1) Examine whether racial/ethnic differences in quality indicators of substance abuse treatment exist. The widely adopted quality indicator measures for outpatient substance abuse treatment, the Washington Circle performance measures of treatment initiation and engagement, will be used to assess treatment quality. 2) Test whether client-, facility-, and community-level predictors of treatment initiation and engagement differ by clients'race/ethnicity;3) Evaluate whether race/ethnicity moderates the relationship between treatment engagement and subsequent treatment outcomes, specifically emergency department visits and detoxification admissions. This study will use administrative data from Massachusetts'publicly-funded outpatient substance abuse treatment services in 2006. The data will be linked with data on emergency department visits across the state. To accomplish the first two aims, multilevel regressions will be employed to account for within-facility correlations of clients'initiation and engagement status. To accomplish the third aim, survival (time-to-event) analyses will be employed. The outcomes will be measured in the year following the index visit to outpatient treatment, controlling for client-, facility-, and community-level factors. Furthering our understanding on racial/ethnic disparities in treatment quality could offer ways for states and programs to improve treatment quality for clients from diverse backgrounds and lead to better treatment outcomes.